Active compound release systems

Abstract

In a therapeutic system such as a plaster for administration of an active compound through the skin and comprising a covering layer which is essentially impermeable to the active compound, an active coupound reservoir layer and a protective layer which can be pulled off and which is essentially impermeable to the active compound, the improvement wherein the reservoir layer contains about 1-30% of active compound in an elastomer mixture comprising a diene rubber which can optionally be copolymerized with an alpha -olefin, mixed with from 0 up to about 70% by weight of a polyisobutylene, polybutadiene oil and/or paraffin oil, and a tackifying resin. Thereby the active compound can be released in regulated relatively large quantity over a prolonged period of time.

We claim: 
     
       1. In a medical plaster comprising a covering layer which is essentially impermeable to the active compound, an active compound reservoir layer and a protective layer which can be pulled off and which is essentially impermeable to the active compound, the improvement wherein the reservoir layer contains about 1-30% of active compound comprising an antiphlogistic in an elastomer mixture comprising a diene rubber which can optionally be randomly copolymerised with an α-olefin, mixed with from 0 up to about 70% by weight of a polyisobutylene, polybutadiene oil and/or paraffin oil, and a tackifying resin. 
     
     
       2. In a therapeutic system comprising a medical plaster for adminstration of an active compound comprising an antipholgistic through the skin, and comprising a covering layer, a reservoir layer which contains the active compound and also contains a polymer, an entraining agent, a resin and a protective layer which can be pulled off, the improvement wherein the polymer of the reservoir layer containing active compounds is diene rubber with at least 30% of the cis 1,4-linkage and a Mooney viscosity (1+4 minutes running time, 100° C.) of about 20-100, which can contain up to 50% of a vinyl-aromatic incorporated randomly, mixed with from 0 up to about 70% by weight of the polymer component of polyisobutylene, the reservoir containing about 1-30% by weight of an antiphlogistic as the active compound. 
     
     
       3. A medical plaster according to claim 1, wherein the reservoir containing active compound comprises about 30-60% by weight of polymer, 30-60% by weight of entraining agent and 2-40% by weight of resin, in addition to the active compound. 
     
     
       4. A medical plaster according to claim 1, wherein the diene rubber comprises butadiene and/or isoprene copolymerised with up to 50% by weight of a vinyl-aromatic. 
     
     
       5. A medical plaster according to claim 1, wherein the diene rubber comprises a polybutadiene rubber with 30-40% of cis 1,4- and 40-60% of trans 1,4 double bonds and a Mooney viscosity of 30-50. 
     
     
       6. A medical plaster according to claim 1, wherein the diene rubber comprises a polybutadiene rubber with more than 80% cis 1,4 content and a Mooney viscosity of 35-55. 
     
     
       7. A medical plaster according to claim 1, wherein the diene rubber comprises a styrene/butadiene rubber with 15-30% by weight of styrene in the polymer and a Mooney viscosity of 30-50. 
     
     
       8. A medical plaster according to claim 1, wherein the diene rubber is mixed with a polyisobutylene with a molecular weight distribution M w  /M n  of 1.5 to 3.5, and an average molecular weight of 30,000 to 4,000,000 g/mol. 
     
     
       9. A therapeutic system according to claim 2, wherein at least one of a paraffin oil and a liquid polybutadiene oil is used as the entraining agent. 
     
     
       10. A medical plaster according to claim 1, wherein the active compound is selected from the group consisting of an antiphlogistic of the formula ##STR5## and esters and amides thereof, in which R 1  -R 5  each independently is hydrogen, halogen, lower alkyl or substituted alkyl, X is N or CH,   Y is hydrogen, a metal ion, alkyl or substituted alkyl,   R is hydrogen, lower alkyl or substituted alkyl,   Ar is aryl, heteroaryl, substituted aryl or substituted heteroaryl,   n and m each is an integer and together total zero, 1 or 2, and   p is zero or 1, with the proviso that Ar is not aryl or heteroaryl if n, m and p each is zero.     
     
     
       11. A medical plaster according to claim 1, wherein the active compound is etofenamat. 
     
     
       12. A medical plaster according to claim 1, wherein the active compound is ketoprofen. 
     
     
       13. A medical plaster according to claim 1, wherein the active compound is acematacin. 
     
     
       14. A medical plaster according to claim 1, wherein the active compound is indoprofen. 
     
     
       15. A medical plaster according to claim 1, wherein the active compound is indometacin.